diff --git a/Dockerfile b/Dockerfile
index e2ff71fd..f6120b71 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -44,6 +44,7 @@ RUN apk --update --no-cache add \
         php7-openssl \
         php7-session \
         php7-xml \
+        php7-simplexml \
         php7-zlib \
         s6